HERA and the asymptotic behaviour of F2p

We examine the recent HERA data on the deep inelastic structure function, F2p. The data are analysed in terms of the 'double scaling' variables, √(1n 1/x /ln ln Q2) and √(ln 1/x /ln ln Q2). Although the data can be well described by the 'double asymptotic scaling' prediction of perturbative QCD, we find that this is not the only possible scenario and hence conclude that, as yet, the HERA data is unable to identify the essential physics driving the small x rise in F2p. (author)